Give 9B62.11 a go. You might have to try a couple of defunct lasers to find
one that works and alignment is a little fussy but it the various lasing
modes you see as the exciting laser warms up and slightly changes frequency
is very neat.

Tappers,
Is there anything useful one can do with a "dead" HeNe laser? I have
one just so folks can see the insides, but I recall reading once that if
the tube is still intact and has a good seal, then somehow one can shine
a working HeNe laser into the "dead" one to show something. Does this
ring a bell to anyone? Thanks.
Adam Beehler